Although the median length of psychotherapy in this country is estimated to be 5-8 sessions, recent epidemiological research has indicated that a small minority of the persons who make a "mental health visit" in a year use the great majority of the outpatient mental health visits provided in that year. This small group of longer-term patients constitutes the bulk of psychotherapeutic practice, and creates a disproportionate impression on mental health professionals. Yet precisely because their treatment covers a considerable span of time, and because they are a small fraction of those who enter treatment, these cases are difficult to study in clinical settings which do not have both a large patient population and a commitment to providing longer-term treatment. Accordingly, longer-term psychotherapy has received little attention in the research literature. To help to remedy this situation, the present study draws on the resources of an appropriate clinical setting in order to (l) identify the distinctive demographic and clinical characteristics of successful and unsuccessful shorter- and longer-term patients, (2) compare and contrast the early therapeutic experiences of successful and unsuccessful shorter- and longer-term cases and, (3) investigate changes in therapeutic process (i.e., phases) over the course of successful and unsuccessful longer-term treatment. This is a naturalistic study of the utilization of psychotherapy. Patients, therapists, and supervisors complete a wide variety of theoretically-based questionnaires and ratings at specific points in the course of treatment. Three months after termination, patients are interviewed regarding their current functioning and help-seeking behavior.